Re: [PATCH v6 10/18] sh/tlb: Convert SH to generic mmu_gather

[John Paul Adrian Glaubitz]

Hi!

On 12/4/19 1:32 PM, Geert Uytterhoeven wrote:
>>>> Cc: Will Deacon <will.deacon@xxxxxxx>
>>>> Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>>>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>>>> Cc: Nick Piggin <npiggin@xxxxxxxxx>
>>>> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
>>>> Cc: Rich Felker <dalias@xxxxxxxx>
>>>> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
>>>
>>> I got remote access to an SH7722-based Migo-R again, which spews a long
>>> sequence of BUGs during userspace startup.  I've bisected this to commit
>>> c5b27a889da92f4a ("sh/tlb: Convert SH to generic mmu_gather").
>>
>> Whoopsy.. also, is this really the first time anybody booted an SH
>> kernel in over a year ?!?
> 
> Nah, but the v5.4-rc3 I booted recently on qemu -M r2d had
> CONFIG_PGTABLE_LEVELS=2, so it didn't show the problem.
> 
>>> Do you have a clue?
>>
>> Does the below help?
> 
> Unfortunately not.
> 
>> diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
>> index 22d968bfe9bb..73a2c00de6c5 100644
>> --- a/arch/sh/include/asm/pgalloc.h
>> +++ b/arch/sh/include/asm/pgalloc.h
>> @@ -36,9 +36,8 @@ do {                                                  \
>>  #if CONFIG_PGTABLE_LEVELS > 2
>>  #define __pmd_free_tlb(tlb, pmdp, addr)                        \
>>  do {                                                   \
>> -       struct page *page = virt_to_page(pmdp);         \
>> -       pgtable_pmd_page_dtor(page);                    \
>> -       tlb_remove_page((tlb), page);                   \
>> +       pgtable_pmd_page_dtor(pmdp);                    \
> 
> expected âstruct page *â but argument is of type âpmd_t * {aka struct
> <anonymous> *}â
> 
>> +       tlb_remove_page((tlb), (pmdp));                 \
> 
> likewise
> 
>>  } while (0);
>>  #endif

Any chance we can have another go at this? The original change

commit c5b27a889da92f4a969d61df77bd4f79ffce57c9 (refs/bisect/bad)
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date:   Tue Sep 4 14:45:04 2018 +0200

    sh/tlb: Convert SH to generic mmu_gather
    
    Generic mmu_gather provides everything SH needs (range tracking and
    cache coherency).

breaks systemd for me on my SH-7785LCR [1].

Adrian

> [1] https://marc.info/?l=linux-kernel&m=159479951822677&w=2

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@xxxxxxxxxx
`. `'   Freie Universitaet Berlin - glaubitz@xxxxxxxxxxxxxxxxxxx
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